This cross-sectional study will examine jobs and perform medical screening of workers who are at risk of developing upper extremity cumulative trauma disorders with the goal of modelling quantitative dose-response relations between job exposures and medical outcomes. The research will be conducted by a team of scientists with backgrounds in industrial hygiene/ergonomics, upper extremity cumulative trauma disorders, occupational medicine, neurology, industrial and operations engineering, electrophysiology, epidemiology, and biostatistics. The specific objectives include: 1. To identity jobs with at least three levels of repetition and with at least 20 workers in each category in the study plants. 2. To quantitatively assess job exposures for repetitiveness and other factors which are known to be potential risk factors for developing CTDs, including force, mechanical stress, posture, vibration and temperature extremes. 3. To perform medical screening of subjects/workers that would include: questionnaire surveys (demographic information, pertinent medical history, occupational history, discomfort/symptom survey), standardized physical examinations of the upper extremities, nonaversive quantitative sensory tests of the upper extremities, strength testing, and limited electrodiagnostic testing of the upper extremities. 4. To model relationships between indices of job exposure (e.g. quantitative rating of repetitiveness) and indices of medical outcomes (e.g. symptoms, physical examination findings, quantitative sensory test results, electrodiagnostic test results, and prevalence of specific CTDs) with the goal of developing quantitative, dose-response relationships between job exposures and medical outcomes. 5. To compare the efficacy of the various medical screening techniques employed to detect CTDs (e.g. to compare the predictive value of quantitative sensory scores in the distal upper extremities to electrodiagnostic test results with regard to identification of possible carpal tunnel syndrome). 6. To make specific recommendations to participating plants and workers about how to reduce ergonomic risk factors identified during the course of this investigation. (If this cross-sectional investigation is successful, then the plants/jobs/workers studied would form the basis of a possible follow-up, prospective study whereby one could assess the medical impact of ergonomic interventions made at the conclusion of the initial cross-sectional investigation).